toluene solubility in water

[ChuckEasley]

I need the solubility of toluene in water at the azeotrope temperature of about 84 C. Even better would be a source of vapor-liquid equilibria data for toluene and water. I have looked in the DECHEMA Liquid-Liquid and Vapor-Liquid data collections, and it is not there.

 

[neerajks4]

is toulene and water miscisible???

 

[EGT01]

Guess I've always thought of toluene and water as being immiscible though toluene does have a very slight solubility in water, 0.05% at 25C per one MSDS. From that, I believe Henry's Law is generally considered to apply for toluene in water.

However, just looking on the internet, I find several references to toluene-water azeotrope but it appears it is in reference to reagent grade toluene that contains water and methods to dry the toluene further. Shows you how much I know.

Checking my trusty Perry's, there is a section on azeotropes that shows the minimum boiling point azeotropic mixture is 55mol% water in toluene (2 phase) at 84.1C, 760 mmHg. I believe this is referred to as a heterogeneous azeotrope as opposed to homogeneous (eg ethanol/water).

 

[ChuckEasley]

I know that toluene is only slightly soluble in water, but I want to know more quantitatively what the solubility is at the azeotropic temperature of 84.1 C. All of the data I have found is at a range of 25 to 30 C. Haven't been able to find solubility data at higher temperatures.

 

[EGT01]

I don't think it would be unreasonable to use Henry's Law data at 25C and 30C to predict a value at 84C but but having data closer would certainly make you feel more comfortable.

Equations for Henry's Law constant generally take the form of
H = EXP( A + B/T)

Perform a data regression of 1/T as x and LN(H) as y to develop an equation for the Henry's Law constant in terms of temperature. Excel does this nicely with A=intercept coefficient and B=X Variable 1 coefficient.

I happened to find the following which gives you a little background regarding the above and another toluene water temperature point at 45C.

http://www.uaf.edu/chem/434f00/henry/henry2.doc

I would be interested to know if anyone has data beyond that listed above.